Friday, January 24, 2014

Book Review for "Drools JBoss Rules 5.x Developer's Guide"

Book Review for "Drools JBoss Rules 5.x Developer's Guide"

Do you have an interest in Rule Engines? Rule Engines have long promised to relieve the programmer of maintenance tasks, to bridge the gap between business user and developer. This book covers JBoss's rule engine (Drools) from the Developer's view.

Drools has expanded beyond it's roots as a rule engine and now offers additional functionality like business process management and complex event processing. (For those not familiar, BPM used to be called 'workflow'-- it means state management for long-running business processes.) CEP deals with detecting conditions in windows of time. For instance, detecting when a specific stock begins trading at discounted prices over a sliding 10 minute timeframe. These features (and more) are available with Drools, many are explained in this book.

By the way, if this book sounds somewhat familiar, it's probably because it's a refresh of the same title targeted towards Drools 5.0. Besides the technical update, there seem to be many small adjustments made to increase readability. If you've seen the first book, you'll want to see this one.

The author goes over the basics of business rules in the first chapters. What a rule engine is, how to use Drools, how to write rules and how to make Domain Specific Languages (DSLs) are all explained.

Central chapters explain some viable use cases for a rule engine-- data validation and transformation. The author provides example scenarios and the rule artifacts needed for the tasks. Through these chapters, additional material about use of Drools is covered.

Later chapters cover testing and application construction. There are a surprising number of nuances to integrating business logic engines into enterprise applications, so this chapter will be of special interest to users who are working to integrate with enterprise frameworks.

Finally, there are some appendices which provide details about setting things up and the sample applications.

All things considered, this book has over 300 pages of valuable content for those interested in using the powerful features of the Drools. If you are a Drools user, you probably owe it to yourself to have a look.